U.S. patent number 7,504,736 [Application Number 11/392,275] was granted by the patent office on 2009-03-17 for semiconductor packaging mold and method of manufacturing semiconductor package using the same.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Sang-Uk Kim, Han-Shin Youn.
United States Patent |
7,504,736 |
Kim , et al. |
March 17, 2009 |
Semiconductor packaging mold and method of manufacturing
semiconductor package using the same
Abstract
A semiconductor packaging mold includes first and second mold
bodies, a cavity defined by the first and second mold bodies to
provide a space for molding a semiconductor package, and a resin
bleed preventing formation on a cavity surface of one of the first
and second mold bodies to suppress resin bleeding.
Inventors: |
Kim; Sang-Uk
(Chungcheongnam-do, KR), Youn; Han-Shin
(Chungcheongnam-do, KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon-si, Gyeonggi-do, KR)
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Family
ID: |
37034372 |
Appl.
No.: |
11/392,275 |
Filed: |
March 28, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060214283 A1 |
Sep 28, 2006 |
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Foreign Application Priority Data
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Mar 28, 2005 [KR] |
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10-2005-0025370 |
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Current U.S.
Class: |
257/796; 257/706;
257/713; 257/787; 257/E21.504 |
Current CPC
Class: |
H01L
21/565 (20130101); H01L 23/4334 (20130101); H01L
2224/48227 (20130101); H01L 2924/01079 (20130101); H01L
2924/15311 (20130101); H01L 2924/16152 (20130101); H01L
2224/32225 (20130101); H01L 2224/73265 (20130101); H01L
24/48 (20130101); H01L 2224/45144 (20130101); H01L
2224/73265 (20130101); H01L 2224/32225 (20130101); H01L
2224/48227 (20130101); H01L 2924/00 (20130101); H01L
2924/15311 (20130101); H01L 2224/73265 (20130101); H01L
2224/32225 (20130101); H01L 2224/48227 (20130101); H01L
2924/00 (20130101); H01L 2224/73265 (20130101); H01L
2224/32225 (20130101); H01L 2224/48227 (20130101); H01L
2924/00012 (20130101); H01L 2924/15311 (20130101); H01L
2224/73265 (20130101); H01L 2224/32225 (20130101); H01L
2224/48227 (20130101); H01L 2924/00012 (20130101); H01L
2924/00014 (20130101); H01L 2924/00014 (20130101); H01L
2224/05599 (20130101); H01L 2224/45144 (20130101); H01L
2924/00014 (20130101); H01L 2224/45144 (20130101); H01L
2924/00015 (20130101); H01L 24/45 (20130101); H01L
24/73 (20130101); H01L 2924/181 (20130101); H01L
2924/181 (20130101); H01L 2924/00012 (20130101) |
Current International
Class: |
H01L
23/28 (20060101); H01L 23/34 (20060101) |
Field of
Search: |
;257/787,706,712,713,796,E21.504 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2-37756 |
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Feb 1990 |
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JP |
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11-220075 |
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Aug 1999 |
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JP |
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0156514 |
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Jul 1998 |
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KR |
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2000-0073112 |
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Dec 2000 |
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KR |
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Other References
English language abstract of Korean Publication No. 2000-0073112.
cited by other .
English language abstract of Japanese Publication No. 11-220075.
cited by other.
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Primary Examiner: Parekh; Nitin
Attorney, Agent or Firm: Marger Johnson & McCollom,
P.C.
Claims
What is claimed is:
1. A semiconductor packaging mold comprising: first and second mold
bodies; a cavity defined by the first and second mold bodies to
provide a space to receive a semiconductor package to be molded;
and a first formation bounding a central portion of a surface of
the cavity, wherein the first formation comprises a groove, wherein
the semiconductor package comprises a heat spreader provided with a
dam corresponding to the groove, and wherein the first formation is
formed to correspond to a matingly compatible second formation
bounding a central portion of a surface of the semiconductor
package to be molded.
2. The mold of claim 1, wherein the first formation is located on
the first mold body, the first mold body being disposed above the
second mold body.
3. The mold of claim 1, wherein the groove is formed in a closed
shape.
4. The mold of claim 3, wherein the closed shape is a circular
shape.
5. The mold of claim 3, wherein a cross sectional shape of the
groove is a semicircular shape.
6. The mold of claim 1, wherein the heat spreader is chosen from
Cu, a Cu alloy, aluminum, and an aluminum alloy.
7. A semiconductor packaging mold comprising: first and second mold
bodies; a cavity defined by the first and second mold bodies to
provide a space to receive a semiconductor package to be molded;
and a first formation bounding a central portion of a surface of
the cavity, wherein the first formation comprises a dam and wherein
the semiconductor package comprises a heat spreader provided with a
groove corresponding to the dam, and wherein the first formation is
formed to correspond to a matingly compatible second formation
bounding a central portion of a surface of the semiconductor
package.
8. The mold of claim 7, wherein the dam is formed in a closed
shape.
9. The mold of claim 8, wherein the closed shape is a circular
shape.
10. The mold of claim 7, wherein the groove and the dam are
matingly compatible in size, shape and location to interlock during
the molding process.
11. A semiconductor packaging mold comprising: a mold body; a
cavity defined by the mold body to provide a space to receive a
semiconductor package to be molded; and a non-planar resin bleed
preventing formation on a surface of the cavity, wherein the
non-planar resin bleed preventing formation comprises a groove, and
wherein the semiconductor package comprises a heat spreader
provided with a dam corresponding to the groove.
12. The mold of claim 11, wherein the non-planar resin bleed
preventing formation corresponds to a matingly compatible formation
of the semiconductor package to be molded.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
This application claims the benefit of Korean Patent Application
No. 10-2005-0025370, filed on Mar. 28, 2005, in the Korean
Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor packaging mold and
a method of manufacturing a semiconductor package using the
same.
2. Description of the Related Art
A semiconductor wafer is cut into a plurality of single
semiconductor chips through a sawing process in an overall assembly
process. Each of the semiconductor chips is mounted on a lead frame
or a basic frame such as a printed circuit board through a die
attaching process. The semiconductor chip, e.g., as mounted on the
frame, goes through a wire bonding process whereby a bond pad of
the chip electrically connects to a connection terminal of the
frame, e.g., by way of a gold wire.
To prevent damage from external impact, the assembly of the
semiconductor chip and the frame, as interconnected by the gold
wire, is encapsulated by a sealant, e.g., a resin such as an epoxy
mold compound, through a molding process.
In recent years, the semiconductor package has been reduced in
thickness and increased in the number of pins and in the clock
speed. Due to this, undesirably, the semiconductor package
generates a large amount of heat. Therefore, many schemes have been
developed for effectively discharging heat, as generated within the
semiconductor package, to an external side of the package.
One of the schemes integrates a heat spreader within the
semiconductor package during the molding process. The heat
generated from the semiconductor package is transmitted to
atmosphere or to the frame through the heat spreader and is thereby
discharged at the external side, thereby protecting electrical
properties of the semiconductor package against heat-related
deterioration.
To maximize the heat discharge efficiency, the heat spreader as
integrated with the semiconductor package is partly exposed at the
external side. To accomplish this exposure, therefore, the molding
process is performed in a state where a surface of the heat
spreader closely contacts a mold cavity surface. In other words,
the process aims to prevent resin from flowing or "bleeding"
between the mold cavity surface and the heat spreader. Thus, the
resin must not cover the external surface of the heat spreader.
Undesirably, the sealing resin sometimes bleeds and thinly covers
the surface of the heat spreader, and a resin bleed defect
results.
FIG. 1 shows a semiconductor package illustrating the resin bleed
defect and FIG. 2 shows an enlarged view of a portion A of FIG.
1.
Referring to FIGS. 1 and 2, a typical semiconductor package 30
includes a basic frame 10 such as a printed circuit board, a
semiconductor chip 14 physically mounted on the basic frame 10 by a
die adhesive 12 and electrically connected to the basic frame 10 by
a gold wire 16. A sealing resin 20 encapsulates the semiconductor
chip 14 on the basic frame 10. To effectively discharge the heat
generated from the semiconductor chip 14 to an external side, a
heat spreader 18 is integrated with the semiconductor chip 14
during a molding process and remains partly exposed as an external
side of the semiconductor package 30. A plurality of solder balls
22 attach on a bottom of the basic frame 10 to serve as external
connection terminals.
In the molding process, to prevent the resin bleed defect, a
surface of the heat spreader, which is to remain exposed, must
accurately and closely contact an upper mold body 24 (FIG. 2) of
the mold. Undesirably, when a ram pressure for filling the sealing
resin in a cavity of the mold is too high, there may be a gap
between the upper mold body 24 and the surface of the heat
spreader. This can allow the sealing resin to bleed into the gap,
thereby causing the resin-bleeding defect.
FIGS. 3 and 4 illustrate a typical method of molding a
semiconductor package.
Referring to FIGS. 3 and 4, a technology of forming a dam 28 on a
heater spreader 18 of a semiconductor package 20' to prevent the
resin bleeding defect is discussed in U.S. Pat. Publication No.
2002/0076856 to Richard W. Wensel, Boise entitled "METHOD AND
APPARATUS FOR TRANSFER MOLDING ENCAPSULATION OF A SEMICONDUCTOR DIE
WITH ATTACHED HEAT SINK" published on Jun. 20, 2002.
FIG. 4 shows an enlarged view of a portion B of FIG. 4.
As shown in FIG. 4, the dam 28 formed on a surface of the heat
spreader 18 is designed to block the undesirable bleeding of the
sealing resin 20. When transfer pressure applied by a ram to
transfer the sealing resin to a cavity of the mold is excessively
high, however, the dam 24 cannot perfectly contact an upper mold
body 24 (FIG. 4). Thus, the dam 28 cannot always effectively block
the bleeding of the sealing resin that causes the resin bleed
defect.
SUMMARY
Embodiments of the present invention provide, among other things, a
semiconductor packaging mold that can suppress the resin bleed by
improving an internal structure of a mold cavity. Embodiments of
the present invention further provide a method of manufacturing a
semiconductor package using such a semiconductor packaging
mold.
In one embodiment, a semiconductor packaging mold comprises first
and second mold bodies; a cavity defined by the first and second
mold bodies to provide a space to receive a semiconductor package
to be molded; and a non-planar resin bleed preventing formation on
a surface of the cavity and formed to correspond to a matingly
compatible formation of the semiconductor package to be molded.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the present
invention will become more apparent by describing in detail
exemplary embodiments thereof with reference to the attached
drawings in which:
FIG. 1 (Prior Art) is a sectional view of a semiconductor package
illustrating a resin bleed defect incurred during a molding
process;
FIG. 2 (Prior Art) is an enlarged sectional view of a portion A of
FIG. 1;
FIGS. 3 and 4 (Prior Art) are sectional views illustrating a
conventional method for molding a semiconductor package;
FIG. 5 is a sectional view of a semiconductor-packaging mold in
accordance with a first embodiment of the present invention;
FIG. 6 is a sectional view of a semiconductor package molded by a
semiconductor-packaging mold in accordance with a first embodiment
of the present invention;
FIG. 7 is a top view of a heat spreader depicted in FIG. 6;
FIG. 8 is a sectional view of a heat spreader depicted in FIG.
6;
FIG. 9 is a sectional view illustrating a method of manufacturing a
semiconductor package in accordance with a first embodiment of the
present invention;
FIG. 10 is an enlarged view when a portion C of FIG. 9 is
connected;
FIG. 11 is a sectional view of a semiconductor-packaging mold in
accordance with a second embodiment of the present invention;
FIG. 12 is a sectional view of a semiconductor package molded by a
semiconductor-packaging mold in accordance with a second embodiment
of the present invention;
FIG. 13 is a sectional view illustrating a method of manufacturing
a semiconductor package in accordance with a second embodiment of
the present invention; and
FIG. 14 is an enlarged view when a portion C of FIG. 13 is
connected.
DETAILED DESCRIPTION
Embodiments of the present invention will now be described more
fully with reference to the accompanying drawings, in which such
exemplary embodiments of the invention are shown. The invention
may, however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein; rather,
these embodiments are provided as thorough and complete disclosure,
and will fully convey the concept of the invention to those skilled
in the art.
First Embodiment: A Resin Bleed Groove Formation
FIG. 5 shows a semiconductor-packaging mold in accordance with a
first embodiment of the present invention.
Referring to FIG. 5, a semiconductor packaging mold of this
embodiment includes first and second mold bodies 102 and 104, a
cavity defined by the first and second mold bodies 102 and 104 to
provide a molding space for a semiconductor package, and a groove
108 formed on a cavity surface of the second mold body 104 to
prevent the resin bleed. That is, a feature of this embodiment is a
resin bleed preventing formation, e.g., a groove formed in a
closed-circle shape. The function of the groove 108 will be
described later.
FIG. 6 shows a semiconductor package formed by the
semiconductor-packaging mold of this embodiment.
Referring to FIG. 6, a semiconductor package 130 includes a basic
frame 110. In the drawing, the basic frame 110 is formed of a
printed circuit board. However, the present invention is not
limited to this case. For example, the basic frame 110 may be
formed of a lead frame. The semiconductor package 130 further
includes a semiconductor chip 114 electrically connected to the
basic frame 110 by a gold wire 116 and physically attached by a die
adhesive. In this embodiment, although the semiconductor chip 114
is connected to the basic frame 110 via the gold wire 116, the
present invention is not limited to this case. For example, the
semiconductor chip 114 may be mounted through a flip chip bonding
method using a solder bump.
The semiconductor package 130 further includes a heat spreader 118
provided with a dam 128 corresponding in shape and size to the
groove 108 (FIG. 5). The heat spreader 118 may be partly exposed to
an external side and covers an upper portion of the basic frame as
well as the semiconductor chip 114. The heat spreader 118 may be
formed of material useful for heat transmission. For example, the
heat spreader 118 may be formed of a material selected from the
group consisting of Cu, a Cu alloy, aluminum, and an aluminum
alloy.
The semiconductor package 130 further includes a sealing resin 120
formed to leave externally exposed a surface portion of the heat
spreader 118 while sealing the upper portion of the basic frame 110
as well as the semiconductor chip 114. A plurality of solder balls
122 attach on a bottom of the basic frame 110 and serve as external
connection terminals. When the basic frame 110 is formed of the
lead frame, leads may be used as the external connection
terminal.
FIG. 7 is a top view of the heat spreader depicted in FIG. 6 while
FIG. 8 is a sectional view of the heat spreader depicted in FIG.
6.
Referring to FIGS. 7 and 8, the heat spreader 118 is formed in a
generally rectangular shape, four corners of which are rounded and
an inclined surface 138 is formed about its edges. The inclined
surface 138 is sealed by the sealing resin in the molding process.
A center portion of the heat spreader 118, e.g., as bounded by the
grove 128, is a flat surface to be left exposed after the molding
process is finished. The closed shape, e.g., circular shaped, dam
128 is formed relative to the exposed flat surface.
FIG. 9 illustrates a method of manufacturing the semiconductor
package in accordance with a first embodiment of the present
invention and FIG. 10 is an enlarged view when a portion C of FIG.
9 is connected.
Referring to FIGS. 9 and 10, the semiconductor packaging mold
provided with the groove 108 formed on the cavity surface of the
second mold body 104 is first provided. In the drawing, although
the cross section of the groove 108 is formed in a semi-circular
shape, the cross section of groove 100 may be formed in variety of
shapes including but not limited to a triangular-shape, a
rectangular-shape or other polygonal-shape. Further, the closed
shape of groove 128, e.g., as seen in FIG. 7, need not be
circular.
Then, the semiconductor package is loaded in the cavity 106. At
this point, the semiconductor package, having at its surface the
dam 128 corresponding in size, shape and location to the groove
108, rests in the cavity 106. The semiconductor package is already
wire-bonded using the gold wire.
Finally, the molding process is performed using the sealing resin
in a state where the groove 108 is interlocked with the dam 128
formed on the semiconductor package. Here, as shown in FIG. 10, the
groove 108 formed on the cavity surface of the second mold body 104
is tightly interlocked with the dam 128 formed on the heat spreader
118 when the first and second molds 102 and 104 are clamped
together. As a result of such mating compatibility, even when the
ram pressure for injecting the sealing resin into the cavity 106 is
increased, the bleeding of the sealing resin can be effectively
blocked, thereby preventing the resin bleed defect.
Second Embodiment: A Resin Bleed Preventing Unit is Dam
FIG. 11 shows a semiconductor-packaging mold in accordance with a
second embodiment of the present invention;
Referring to FIG. 11, a semiconductor-packaging mold of this
embodiment includes first and second molds 202 and 204, a cavity
defined by the first and second molds 202 and 204 to provide a
molding space for a semiconductor package, and a dam 208 formed on
a cavity surface of the second mold body 204 to prevent the resin
bleed. That is, a feature of this embodiment is that a resin bleed
preventing unit is formed of a dam, and a groove corresponding to
the dam 208 is formed on a heat spreader of a semiconductor
package. Since other parts of this embodiment are similar to those
of the first embodiment, the detailed description thereof will be
omitted herein.
FIG. 12 shows a semiconductor package molded by the
semiconductor-packaging mold of this embodiment.
Referring to FIG. 12, a semiconductor package 230 includes a basic
frame 210 and a semiconductor chip 214 electrically connected to
the basic frame 210. A heat spreader 218 provided with the groove
228 corresponding to the dam (referring to the reference numeral
208 of FIG. 11) is partly exposed to an external side while
covering an upper portion of the basic frame 210 as well as the
semiconductor chip 214. A sealing resin 220 is formed to leave
exposed a part of the heat spreader 218 while sealing the upper
portion of the basic frame 210 as well as the semiconductor chip
214. A plurality of solder balls 222 attach on a bottom of the
basic frame 210 and serve as external connection terminals. It will
be understood by those of ordinary skill in the art that various
modifications of the semiconductor package 230 will be
possible.
FIG. 13 illustrates a method of manufacturing the semiconductor
package in accordance with a first embodiment of the present
invention and FIG. 14 is an enlarged view when a portion C of FIG.
13 is interlocked.
Referring to FIGS. 13 and 14, the semiconductor packaging mold
provided with the dam 208 formed on the cavity surface of the
second mold body 204 is first provided. Then, the semiconductor
package is loaded in the cavity 206. At this point, the heat
spreader of the semiconductor package, having at its surface with
the groove 218 corresponding to the dam 208, rests in the cavity
206. The semiconductor package is already wire-bonded using the
gold wire.
Finally, the molding process is performed using the sealing resin
in a state where the dam 208 formed on the cavity surface of the
second mold body 204 is interlocked, e.g., matingly compatible,
with the groove 228 formed on the semiconductor package. Here, as
shown in FIG. 14, the dam 208 formed on the cavity surface of the
second mold body 204 is tightly interlocked with the groove 228
formed on the heat spreader 218 when the first and second mold
bodies 202 and 204 are clamped. As a result, even when the ram
pressure for injecting the sealing resin into the cavity 206 is
increased, the bleeding of the sealing resin can be effectively
blocked, thereby preventing the resin bleed defect. At this point,
since the dam 208 and the groove 228 are formed in a closed shape,
e.g., a circular shape, the sealing resin does not bleed to the
inner portion enclosed or bounded by the groove 228 even after the
molding process is finished.
According to the above-described embodiments, by physically
modifying the structure of the mold to disallow the resin to bleed
during the molding process, the resin bleed defect can be
prevented, thereby improving the thermal property of the
semiconductor package.
While embodiments of the present invention have been particularly
shown and described, it will be understood by those of ordinary
skill in the art that various changes in form and details may be
made therein without departing from the spirit and scope of the
present invention as defined by the following claims.
For example, in the above embodiments, although a BGA package with
the heat spreader is shown, the present invention is not limited to
this case. For example, the present invention may be applied to
other semiconductor packages such as a TSOP, TQFP, QFN, and CSP.
Although a surface structure corresponding to the resin bleed
preventing unit of the mold is formed on the heat spreader, the
present invention is not limited to this case. For example, the
surface structure may be formed on a lead frame or a printed
circuit board.
* * * * *